After Effects Rendering - What Are Some Things to Look Out for in a Third Party Renderer?

The main thing you're going to have to realize is the main, the main four renderers. Redshift, Arnold, Octane and physical all run on a computer's CPU. Physical will actually run faster than redshift but it won't be as fast as multi-GPU systems. You'll need an Nvidia card hooked up to your Mac or PC if you want to render in real time.